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Product Description
MOTOR STARTING
Two types of compressor motor starting are available:
Across-the-Line and optional Wye-Delta Open Tran-
si tion Start er.
Across-the-Line starters will utilize one contactor and
one start relay per compressor. The optional Wye-Delta
start er utilizes 4 motor contactors, a transition delay
re lay, a start relay, and a start-wye relay.
The Wye-Delta start allows inrush current to be limited
to approximately 33% LRA for the fi rst 4 to 7 sec onds,
with current increasing to normal running cur rent when
the Delta connection is completed.
When the micro initiates a start signal at Relay Output
Board #1 (SYS 1) Terminal 20 or Relay Output Board
#2 (SYS 2) Ter mi nal 20 to run a com pres sor, the 1CR
(SYS 1) or 2CR (SYS 2) relay is en er gized. The tran-
si tion of the 1CR (SYS 1) or 2CR (SYS 2) relay contacts
en er giz es the 1S (SYS 1) or 2S (SYS 2) relay approx.
16ms later. The 1S/2S con tacts in turn en er gize the 1M
(SYS 1) or 3M (SYS 2) mo tor con tacts 16ms later. This
com pletes the "WYE" con nec tion of the motor start.
At the same time, the normally closed 1S/2S auxiliary
in ter lock con tact opens pre vent ing the 2M and 1 TRX
(SYS 1) or 4M and 2 TRX (SYS 2) mo tor contactors
from en er giz ing. 2 sets of aux il ia ry con tacts from 1M
(SYS 1) or 3M (SYS 2) close, in ter lock ing the 1M (SYS
1) or 3M (SYS 2) contactors, keep ing them en er gized
in par al lel with 1S (SYS 1) or 2S (SYS 2).
The "WYE" connection of the motor start is enabled
for 4 to 7 seconds depending upon motor current as
sensed by the microprocessor. The tran si tion to Delta
takes 7 seconds if current is below 110% FLA. If mo-
tor current exceeds 110% FLA, the transition is made
to Delta as long as the WYE has been enabled for at
least 4 seconds.
After the "WYE" connection is enabled for 4 to 7
sec onds, the 1TR (SYS 1) or 2TR (SYS 2) transition
delay relay is enabled by the microprocessor from Relay
Out put Board #1 Terminal 8 (SYS 1) or Relay Out put
Board #2 Terminal 6 (SYS 2). The 1TR (SYS 1) or 2TR
(SYS 2) contacts open, de-energizing 1S (SYS 1) or 2S
(SYS 2). 1M (SYS 1) or 3M (SYS 2) remain energizes
through 2 sets of interlocking con tacts 1M (SYS 1) or
3M (SYS 2). Open ing of the 1TR (SYS 1) or 2TR (SYS
2) con tacts deenergizes 1S/2S and clos es the nor mal ly
closed 1S (SYS 1) or 2S (SYS 2) con tacts, en er giz ing,
1TRX (SYS 1) or 2TRX (SYS 2). 1TRX or 2TRX
20
subsequently energizes motor contactor 2M (SYS 1)
or 4M (SYS 2), com plet ing the "DELTA" con nec tion
of the motor.
Systems 3 and 4 operate in a similar
sequence
1TR, 1TRX, 2TR, 2TRX, 3TR, 3TRX,
4TR, and 4TRX are NOT "timing "
relays. These devices are simply pilot
relays identical to 1CR-4CR.
KEYPAD CONTROLS
Display
Parameters are displayed in English (°F and PSIG) or
Metric (°C and Bars) units, and for each circuit, the
following items can be displayed:
• Return and leaving chilled liquid, and ambient
tem per a ture.
• Day, date and time. Daily start/stop times. Holiday
and Manual Override status.
• Compressor operating hours and starts. Auto-
matic or manual lead/lag. Lead compressor iden-
ti fi ca tion.
• Run permissive status. No cooling load condition.
Com pres sor run status.
• Anti-recycle timer and anti-coincident start timer
sta tus per compressor.
• System suction (and suction superheat), discharge,
and oil pressures and temperatures.
• Percent full load compressor motor current per
phase and average per phase. Compressor ca pac i ty
con trol valve input steps.
• Cutout status and setpoints for: supply fl uid tem-
per a ture, low suction pressure, high discharge
pres sure and temperature, high oil temperature,
low and high am bi ent, phase rotation safety, and
low leav ing liq uid tem per a ture.
• Unloading limit setpoints for high discharge pres-
sure and compressor motor current.
• Status of: evaporator heater, condenser fans, load
and unload timers, chilled water pump.
• "Out of range" message.
• Up to 6 fault shut down conditions. (4 in YCAS 3
Compressor and YCAS 4 Compressor).
FORM 201.19-NM6 (804)
YORK INTERNATIONAL
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Troubleshooting
